Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Research shows why low vitamin D raises heart disease risks in diabetics

25.08.2009
Low levels of vitamin D are known to nearly double the risk of cardiovascular disease in patients with diabetes, and researchers at Washington University School of Medicine in St. Louis now think they know why.

A healthy macrophage cell, at left, with sufficient vitamin D. On the right, a macrophage with inadequate vitamin D has become clogged with cholesterol, an early marker of atherosclerosis.

They have found that diabetics deficient in vitamin D can't process cholesterol normally, so it builds up in their blood vessels, increasing the risk of heart attack and stroke. The new research has identified a mechanism linking low vitamin D levels to heart disease risk and may lead to ways to fix the problem, simply by increasing levels of vitamin D.

"Vitamin D inhibits the uptake of cholesterol by cells called macrophages," says principal investigator Carlos Bernal-Mizrachi, M.D., a Washington University endocrinologist at Barnes-Jewish Hospital. "When people are deficient in vitamin D, the macrophage cells eat more cholesterol, and they can't get rid of it. The macrophages get clogged with cholesterol and become what scientists call foam cells, which are one of the earliest markers of atherosclerosis."

Macrophages are dispatched by the immune system in response to inflammation and often are activated by diseases such as diabetes. Bernal-Mizrachi and his colleagues believe that in diabetic patients with inadequate vitamin D, macrophages become loaded with cholesterol and eventually stiffen blood vessels and block blood flow.

Bernal-Mizrachi, an assistant professor of medicine and of cell biology and physiology, studied macrophage cells taken from people with and without diabetes and with and without vitamin D deficiency. His team, led by research assistants Jisu Oh and Sherry Weng, M.D., exposed the cells to cholesterol and to high or low vitamin D levels. When vitamin D levels were low in the culture dish, macrophages from diabetic patients were much more likely to become foam cells.

In the Aug. 25 issue of the journal Circulation, which currently is available online, the team reports that vitamin D regulates signaling pathways linked both to uptake and to clearance of cholesterol in macrophages.

"Cholesterol is transported through the blood attached to lipoproteins such as LDL, the 'bad' cholesterol," Bernal-Mizrachi explains. "As it is stimulated by oxygen radicals in the vessel wall, LDL becomes oxidated, and macrophages eat it uncontrollably. LDL cholesterol then clogs the macrophages, and that's how atherosclerosis begins."

That process becomes accelerated when a person is deficient in vitamin D. And people with type 2 diabetes are very likely to have this deficiency. Worldwide, approximately one billion people have insufficient vitamin D levels, and in women with type 2 diabetes, the likelihood of low vitamin D is about a third higher than in women of the same age who don't have diabetes.

The skin manufactures vitamin D in response to ultraviolet light exposure. But in much of the United States, people don't make enough vitamin D during the winter — when the sun's rays are weaker and more time is spent indoors.

The good news is when human macrophages are placed in an environment with plenty of vitamin D, their uptake of cholesterol is suppressed, and they don't become foam cells. Bernal-Mizrachi believes it may be possible to slow or reverse the development of atherosclerosis in patients with diabetes by helping them regain adequate vitamin D levels.

"There is debate about whether any amount of sun exposure is safe, so oral vitamin D supplements may work best," he says, "but perhaps if people were exposed to sunlight only for a few minutes at a time, that may be an option, too."

He has launched a new study of diabetics who are both deficient in vitamin D and have high blood pressure. He wants to learn whether replacing vitamin D will lower blood pressure and improve blood flow. For this study, Bernal-Mizrachi is recruiting patients with type 2 diabetes ages 30 to 80 who are not taking insulin to control their blood sugar. Study volunteers also must have high blood pressure.

For more information, contact mpetty@DOM.wustl.edu or call (314) 362-0934.

Oh J, Weng S, Felton SK, Bhandare S, Riek A, Butler B, Proctor BM, Petty M, Chen Z, Schechtman KB, Bernal-Mizrach L, Bernal-Mizrachi C. 1,25 (OH) vitamin D inhibits foam cell formation and suppresses macrophage cholesterol uptake in patients with type 2 diabetes mellitus. Circulation, vol. 120(8);pp. 687-698. Aug. 25. 2009. Published online August 10, 2009 doi:10.1161/CIRCULATIONAHA.109.856070

Funding for this research comes from a grant from the American Diabetes Association, the National Institutes of Health — through grants awarded to the Washington University Diabetes Research and Training Center and the Clinical Nutrition Research Unit — and the David M. and Paula S. Kipnis Scholar in Medicine Award.

Washington University School of Medicine's 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's Hospitals. The School of Medicine is one of the leading medical research, teaching, and patient care institutions in the nation, currently ranked third in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's Hospitals, the School of Medicine is linked to BJC HealthCare.

Jim Dryden | EurekAlert!
Further information:
http://www.wustl.edu

More articles from Health and Medicine:

nachricht One gene closer to regenerative therapy for muscular disorders
01.06.2017 | Cincinnati Children's Hospital Medical Center

nachricht The gut microbiota plays a key role in treatment with classic diabetes medication
01.06.2017 | University of Gothenburg

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

Im Focus: Optoelectronic Inline Measurement – Accurate to the Nanometer

Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.

New Manufacturing Technologies for New Products

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Hubble captures massive dead disk galaxy that challenges theories of galaxy evolution

22.06.2017 | Physics and Astronomy

New femto-camera with quadrillion fractions of a second resolution

22.06.2017 | Physics and Astronomy

Rice U. chemists create 3-D printed graphene foam

22.06.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>